While governor, Ms. Palin jammed through a tax hike on oil profits as crude prices doubled between 2006 and 2008. Oil and natural-gas royalties and taxes account for roughly 90% of state coffers. Surging oil profits also helped prop up the state’s economy, personal incomes and tax revenues. While U.S. GDP plunged between 2006 and 2009, Alaska’s economy grew by a compounded annual 4.4%—the most nationwide.

Mr. Parnell, the former lieutenant governor, assumed office in July 2009 after Ms. Palin stepped down. The new governor inherited an economic crisis of Ms. Palin’s making. Oil profits subsequently plunged while drillers disembarked for Texas, Oklahoma and North Dakota. Alaska’s crude production has fallen by 20% since 2009.

Last year Alaska’s GDP contracted by 2.5%—the only state to record negative growth. The Republican governor sought to stabilize volatile revenues and stimulate investment by reforming Ms. Palin’s progressive oil tax. Ms. Palin responded by throwing her weight behind the August referendum.

A slim majority of voters rejected the ballot measure, yet the populist furies fueled Mr. Walker’s rise. Although most people have made up their minds and or have voted already. Two weeks before the election, Ms. Palin formally endorsed the Walker-Mallott “Unity Ticket” on the pretext of encouraging political comity in Juneau. “This strong independent ticket represents an Alaskan-sized heart, putting people over party machine politics and Alaskans over egos,” she declared.

Ms. Palin is not overwhelmingly popular in her home state—a Public Policy Polling survey in August showed that just 36% of voters statewide view her favorably—but she does carry clout among anti-establishment conservatives. Given that the election appears to have been decided by fewer than 5,000 votes, and that Republican Dan Sullivan topped incumbent Democratic Sen. Mark Begich by nearly 8,000.